Role of parathyroid hormone and vitamin D supplementation in stroke among patients on peritoneal dialysis

Abstract

Background Continuous ambulatory peritoneal dialysis (CAPD) patients have a high incidence of stroke and commonly have increased parathyroid hormone levels and vitamin D insufficiency. We seek to investigate the incidence of stroke and the role of parathyroid hormone and vitamin D supplementation in stroke risk among CAPD patients.Methods This is a retrospective study enrolled a Chinese cohort of 980 CAPD patients who were routinely followed up in our department. The demographic and clinical data recorded at the time of initial CAPD and during follow-up time are collected. The included cases were separated into nonstroke and stroke groups. The role of parathyroid hormone and vitamin D supplementation for stroke in CAPD patients is evaluated. The primary endpoint is defined as the first-time occurrence of stroke, and composite endpoint events are defined as death or switch to hemodialysis during follow-up.Results A total of 757 eligible CAPD patients with a mean follow-up time of 54.7 (standard deviation (SD) 33) months were included in the study. The median incidence of stroke among our CAPD patients was 18.9 (IQR, 15.7 - 22.1) per 1000 person-years. A significant nonlinear correlation between baseline iPTH and hazard of stroke (p value of linear association = 0.2 and nonlinear association = 0.002) was observed in our univariate Cox regression analysis, and low baseline iPTH levels (≤150 pg/ml) were associated with an increased cumulative hazard of stroke. Multivariate Cox regression analysis indicated a significant interaction effect between age and iPTH after adjusting for other confounders. Vitamin D supplementation during follow-up was a predictive factor for stroke in our cohort.Conclusions CAPD patients suffered a high risk of stroke. Lower iPTH levels were significantly associated with an increased risk of stroke. Vitamin D supplementation is an independent predictive factor for stroke among CAPD patients.